Gas burner



' sept. 24, 1940. A. Smm

GAS BURNER Filed Feb. 18, 1938 Patented spt.'z4,1s4o

'UNITED STATES Gas BURNER Auburn smith, columbus, ohio ApplicationFebruar-yrs, 193s, ser1a1N0.'191,21 4 v u V` (01.158-99) 1 Claim.

This invention relates .toA gas burners and has particular reference togas' burners .ofthe low- -pressure jet inspirator type wherein fuel gas,

Y. under ordinary main pressure, is the motivating fluid and atmosphericair the induced fluid, the

- construction of the burner providing automatically for the propermixing and proportional blending of the fluids comprising the finalcombustible.

mixture.

An outstanding object of the present invention Sresides in theprovisionof a simple and efficient gas burner primarily constructed and adapted'for use in ordinarycoal burning furnaces ofthe type widely employed inconnection with residence heating systems.

The convenience and usefulness of fuel gas as a heat source inthe/operation of house heating systems are well recognized.. However, inmost localities, the relative higher cost of fuel gas in comparison withsolid fuels, such as coal or coke, militates against its general use.Therefore, during cold winter periods, when fuel demand is heavy, it isconsidered desirable by many to burn the vmore economical solid fuels.but during periods of milder temperature,whenv solid fuel fires areldifficult and troublesome -v4to maintain, it is quite desirable to usegas as the source of heat. Hitherto, thisfselected and seasonal use ofgaseous and solid fuels has been accomplished by the employment ofeither separately constructed furnaces or by means of combination unitshavingspaced combustion chambers specifically adapted and constructedfor the fuels burned therein. Such equipment, however, is too costly toadmit of popular use thereof, since installation expenses are high and,moreover, a considerable amount of floor space is required which, quiteoften, is not readily available.

It is, therefore, one ofthe mainobjects of the f present invention toprovide an improved 'gas burner of sturdy, simple and economicalconstruction which may be readily installed Vin or removed frorn thefuel burning chamber of an ordinary coal furnace, this beingaccomplished without involving any material `change or alteration in theconstructional features of the furnace so that, in a minimum of time andat low expense, such a furnace may be conveniently adapted for theefficient burning of either coal or gas.

Another object of the invention resides in the provision of an auxiliarygas burner for coal furnaces so constructed and mounted in the interiorr letof the burner against the inner surfaces of `the furnace fuel bowl,whereby to quickly and- :taken through the furnace in the planeof its 25my improved gas burner in its operating position 'in relation to thewalls of the furnace fuel bowl;

PATENT oFFicE ofthe furnace Aas to cause circular orswirling impingementof the flames issuing from the outeconomically raise the temperature ofthe' heat 5 transferring .surfaces of the furnace through direct andprolonged contact of the gas burner flames therewith.

A still further object resides in a gas burner' havinga wide combustionrange and one which 10 is not likely to back-fire even though the fuelpressure may be reduced to a minimum, to the end of providing a burnerwhich maybe safely used and operated in the heating system of anordinary residence without requiring undue at- 15 tention or theservlcesof a -skilled operator.

Further vobjects and advantages will become apparent as the descriptionproceeds.

In the accompanying drawing:

Fig. 1 is a sectional perspective view taken 20 through an ordinary coalburning furnace and disclosing the operating position of the auxiliarygas burner comprising the present invention therein; Flg. 2 isahorizontal sectional view fuel admitting door opening and disclosing inplan Fig. 3 is a horizontal lsectional' view taken through my improvedgas burner. f 30 Fig. 4 is a transverse sectional view, the. plan ofwhich being indicated by the line IV- IVof Fig. 5 is a similar view onthev line V--V of Fig. 3. f

While the invention is susceptible of various modifications andalternative constructions,=I have shown in the drawing and will hereinde-y scribe in detail the vpreferred embodimentther y of, but it is tobe understood that Ido -not there- 40 by intend to limit the inventiontofthe-embodiment disclosed, but intend to cover all modifications andalternative 'constructions falling within the spirit and scope oftheinvention as expressed in the appended claims. 45

Referring more particularly to the drawngthe numeral I designates theouter casing of an ordinary hand-fired coal burning furnace. Providedwithin the casing is the usual ash pit 2, grates 3; a fuel receivingbowl 4, smokeiring 5 and a plenum chamber 6.' Normally solid fuels areintroduced into the bowl 4 and are deposited on the grates 3 by beingmanually introduced into the furnace through the fuel admitting .l

opening the front of the latter being normally closed by ka removabledoor, not shown. The smoke ring 5 communicates with a flue 8 leading toa chimney or other point of smoke outlet, the flue being provided withthe customary damper valve S, which may be set` to obtain desired draftconditions within the combustion chamber I0 of the furnace, formed bythe bowl 4.

The gas burner II, comprising the present invention, has beenparticularly designed for use as an auxiliary heat-producing means in astandard coal burning furnace of the type set forth, in order that sucha furnace may be con- /veniently and economically operated, especiallyduring periods of relatively low fuel demand. In the specific form ofthe burner illustrated, the same comprises an air supplying duct I2,which preferably consists of inner and outer sections I2a and I2b,respectively, secured together as at I3, to form a continuous conduit ofsubstantially uniform diameter throughout its length and open at bothends. The duct, as shown, is adapted to be positioned in the fueladmitting opening l of the furnace and preferably to one side thereof.In this instance, the exterior of the duct is equipped with a bracket I4by which the duct may be conveniently positioned in one of the lowercorners of the transversely rectanguiar opening l'. A

With the 4burner occupying the position disclosed in the drawing, theordinary outer door or closure of the opening I is removed from thefurnace casing, and a sheet or panel i5 of asbestos or other heatinsulating material substituted therefor by which the front of theopening 1 is closed. The sheet or panel l5 is formed with an opening ofsumcient diameter to receive the outwardly projecting end of the ducti2, as disclosed in Fig. 2.

The inner section Ic of the duct is disposed substantially within theconfines of the combustion chamber I@ and is formed with an angulariyand downwardly directed burner exten,

sion I6, which lies closely adjacent to the inner wall of the bowl 4.The extension I6 has its longitudinal axis disposed at an angle of apnproximately 45 degrees to the longitudinal axis of the main body portionof the duct occupying and extending through the furnace opening l. Theside walls of the extension converge slightly toward the inner end toprovide a somewhat restricted outlet.

Disposed axially within the angularly extending portion I6 of the ductis an elongated mixer tube I'I of suitable form. In the presentinstance, the tube I1 is provided with an inwardly flaring passage ofprogressively increasing diameter toward the outlet end of the burner.The inlet end of the tube is smoothly rounded on a relatively largeradius, as indicated at IB, while the outlet or discharge end of thetube is smoothly rounded on a relatively smaller radius, as indicated atI9. Open webs or spiders 20 are disposed in the angular extension I6 ofthe duct in order to effect the axial support of the tube I1 within theangular extension of the duct, and with the outer Walls of said tubespaced from the inner adjacent walls of the extension I6 to provide anannular and open-endedair space 2l for the travel of air throughthe'extension I6 around or exteriorly of the tube il.

Extending longitudinally of the main body portion of the duct is a gassupply pipe 22, which has its inner end threaded to receive a jet nozzle23, the latter being formed with an angular head 24 which is disposed inspaced relationr from the inner end IB of the tube I'I but in axialalignment therewith.. It will be understood that the outer end of thehead 2H may be provided with one or more restricted orifices for thedischarge of a hydrocarbon fuel gas under city main pressure in the formof one or more inspirating jets.

In the operation of the burner, atmospheric air enters the open outerend of the duct I2, which projects beyond the contines of the casing I.Gas under suitable pressure issues from the orice or orices formed inthe head 24 and passes under relatively high velocity into the enlargedinlet'end of the mixing tube I'l. An inspirator action is thus set up bywhich a cer. tain amount of primary air obtained from the interior ofthe duct is drawn 'into the tube I'l with the gas stream passingtherethrough so that a primary fuel mixture, composed of fuel gas and alimited amount of air, is produced in the tube I1. Ordinarily thismixture does not burn in said tube because of its velocity of travel andthe limited amount of atmospheric oxygen contained therein.- Finalcombustion, however, is obtained by the secondary air, discharged fromthe angular extension IB of the duct, combining with the primary mixtureand with such oxygen that may exist in the atmosphere of the chamber I0.Combustion of the final fuel mixture, however, takes place followingdischarge of the gaseous iiuids forming the mixture from the angularlydirected portion of the duct.

The combustion flames are so directed as to impinge the inner surfacesof the bowl 4 and travel in a generally circular path around the bowl,as disclosed by the arrows in Fig. 2. The flame is directed generallydownwardly in the bowl by reason of the angular disposition of. theburner head. Preferably, a bed of ashes, as indicated at 25,'ismaintained on the grates 3 in order to better regulate draft conditionswithin the combustion chamber of the furnace. In the operation of theburner, the ash pit door 26 of the furnace and its associated draftcontrols are kept closed.

Due to the angularity of the burner head and its position within thechamber II), prolonged flame travel is obtained due to the swirl of theflame in the bottom of the chamber ID. Also, improved heat transfer issecured due to the wiping actionof the hot gases of combustion directlycontacting with the walls 'of the bowl 4. The walls of said bowl areuniformly heated by reason of the spinning motion of the burner flamesand there exists ordinarily but an immaterial differential between thetemperature of the bowl wall more closely adjacent the outlet of theburner and the wall on the opposite side of the bowl as regards saidburner. Excess pressures within the chamber I0. which lmay exist at thetime the operation of the burner is commenced, nd ready relief throughthe duct I2, without interfering with sustained combustion occurring atthe outlet of the burner head within the chamber I0. The endof the gassupply pipe 22 disposed exteriorly of the furnace casing terminates inan elbow 2l and is united with a short pipe exten'- sion 28 in which maybe arranged a thermostatically controlled valve 29. The extension 28,beyond the valve 29 is joined with a removable coupling 30 carried by astationary gas supply pipe 3|. In the pipe 3i, there may be arranged acontrol valve 32, either manually or automatically regulated, to governthe delivery of fuel gas to the burner. Also, a pilot line 33 leads fromthe pipe extension 28 to the head of the burner, so that a constantsupply of gas for pilot purposes may be provided at the head of theburner to insure continuity of operation. i

A thermostat element 34, governing the operation of the valve 29, isdisposed in or contiguous to the pilot flame so that if the lattershould become extinguished, the valve 29 will be closed to prevent theaccumulation of unburned fuel gases in the chamber I0. The flow of airinto the outer end of the duct I2 may be controlled in volume by theinclusion of an adjustable shutter 35 which is mounted for 'movementtoward and away from the open outer end of the duct. The adjustedpositions of the shutter may be maintained by the use of .a set screw36.

To install the gas burner comprising the presenrI invention in a coalburning furnace of the type set forth, it is merely necessary to removethe usual door closing the fuel admitting opening 1. This may be readilyaccomplished by taking the door oi its hinged mountings. The gas burneris then positioned in said opening and in the furnace as disclosed inFig. 2 and the asbestos plate or panel l5 applied to seal the entranceto the opening 1. The gas supply pipes 22 and 28 form constituent partsof the burner assembly and it is therefore merely necessary to operatethe coupling to unite these pipes with the sta.-

tionary gas pipe 3| to complete the installation. Similar convenience isof course obtainable in the matter of removing the burner from thefurnace. Usually with the gas supply pipe 3| in position, it is only amatter of a few minutes time to either make or remove the installation.

What is claimed is:

In apparatus for firing a house-heating furnace With fuel gas instead ofsolid fuel, the furnace having a repot and a redoor opening; thecombination of an air supply conduit extending through said redooropening and terminating adjacent said iirepot, an air nozzle extendingtoward the rcpot from said conduit and forming in effect a continuationof the latter for supplying secondary air, a mixing tube interiorly ofsaid air nozzle arranged to discharge a mixture into said repot, a gassupply pipe Within said conduit, terminating adjacent said air nozzleand arranged to direct fuel gas ,into said mixing tube, and meansscaling the conduit and firedoor `against inflow of air therebetween;whereby to induce primary air from said conduit into said mixing tube toprovide a combustible mixture issuing from the outer end of the tube,and to direct secondary air from said conduit through said air nozzleadjacent the outlet of the mixing tube.

AUBURN SMITH.

